
\((A-A)(A-A)= \mathbb {F}_p\)  when \(|A| > p^{3/4}\)  (Hart, Iosevich, and Solymosi [1]}).

\(|(A-A)(A-A)| = \Omega (p)\)  when \(|A| = \Omega ( p^{2/3})\)  (Bennet, Hart, Iosevich, Pakianathan, and Rudnev [2]}).

\(\underbrace{(A-A) \dots (A-A)}_\text{$k$ terms} = \mathbb {F}_p\)  when \(|A| = \Omega (p^{1/2})\)  for some \(k = O(\log \log (p))\)  independent of \(A\)  (Balog [3]}).

